In general, solid inks (also referred to as phase change inks or hot melt inks) are in the solid phase at ambient temperature, but exist in the liquid phase at the elevated operating temperature of an ink jet printing device. At the jet operating temperature, droplets of liquid ink are ejected from the printing device and, when the ink droplets contact the surface of the recording substrate, either directly or via an intermediate heated transfer belt or drum, they quickly solidify to form a predetermined pattern of solidified ink drops. Phase change inks have also been used in other printing technologies, such as gravure printing.
Phase change inks for color printing typically comprise a phase change ink carrier composition which is combined with a phase change ink compatible colorant. A series of colored phase change inks can be formed by combining ink carrier compositions with compatible subtractive primary colorants. The subtractive primary colored phase change inks can comprise four component dyes, namely, cyan, magenta, yellow and black, although the inks are not limited to these four colors. These subtractive primary colored inks can be formed by using a single dye, a single pigment, a mixture of dyes, a mixture of pigments, or a combination thereof.
U.S. patent application Ser. No. 12/704,194, of Marcel P. Breton et al., entitled “Curable Solid Ink Compositions,” which is hereby incorporated by reference herein in its entirety, describes a curable solid ink composition including a curable component, a non-curable component including an ethoxylated octylphenol derivative, a photoinitiator, and a colorant. The curable solid ink composition has a viscosity in the range of less than 10 cPs at 90° C., a shrinkage value of less than 3%, and a superior curing rate compared to existing curable solid ink compositions. The ethoxylated octylphenol derivatives may be prepared by reacting an ethoxylated octylphenol, a linear alcohol, and diisocyanates, or polyisocyanates.
U.S. patent application Ser. No. 12/642,538, of Marcel P. Breton et al., entitled “Curable Solid Ink Compositions,” which is hereby incorporated by reference herein in its entirety, describes a radiation curable solid ink composition comprising at least one curable wax that is curable by free radical polymerization; at least one monomer, oligomer, or prepolymer; at least one non-curable wax; at least one free-radical photoinitiator or photoinitiating moiety; and a colorant; wherein the components form a curable ink composition that is a solid at a first temperature of from about 20 to about 25° C.; and wherein the components form a liquid composition at a second temperature of greater than about 40° C.
U.S. patent application Ser. No. 12/835,198, of Marcel P. Breton et al., entitled “Radiation Curable Solid Ink Compositions Suitable For Transfuse Printing Applications,” which is hereby incorporated by reference herein in its entirety, describes curable solid inks, such as radiation-curable solid inks, and their use in forming images, such as through transfuse printing, including radiation-curable solid inks, such as ultraviolet light curable phase change inks, that comprise curable and non-curable waxes.
While currently available ink compositions are suitable for their intended purposes, a need remains for curable solid and paste inks that have lower jetting temperatures, faster phase change characteristics, low energy requirements for spreading and printing, excellent curing performance, increased hardness after curing, and low shrinkage characteristics. There further remains a need for low energy, low total cost of ownership solid and paste inks and processes that further provide high quality imaging characteristics.